81570 has 16 divisors (see below), whose sum is σ = 195840. Its totient is φ = 21744.

The previous prime is 81569. The next prime is 81611. The reversal of 81570 is 7518.

It is a happy number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 81570.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1330 + ... + 1389.

It is an arithmetic number, because the mean of its divisors is an integer number (12240).

2⁸¹⁵⁷⁰ is an apocalyptic number.

81570 is an abundant number, since it is smaller than the sum of its proper divisors (114270).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97920).

81570 is a wasteful number, since it uses less digits than its factorization.

81570 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2729.

The product of its (nonzero) digits is 280, while the sum is 21.

The square root of 81570 is about 285.6046218113. The cubic root of 81570 is about 43.3687416052.

The spelling of 81570 in words is "eighty-one thousand, five hundred seventy".